Agilent ICP-MS Journal (November 2021, Issue 86)

Significance of the Topic

Cannabis and hemp products have surged in recreational and medical markets, creating a critical need for reliable heavy metal analysis. Semiconductor manufacturing demands ever tighter impurity controls, while regulatory agencies enforce strict limits on species like hexavalent chromium. Advanced ICP-MS techniques and consumables now enable high-throughput, sensitive, and species-specific analysis to ensure product safety and compliance.

Objectives and Study Overview

This issue highlights three advances: 1) AOAC’s new microwave digestion ICP-MS method for quantifying arsenic, cadmium, mercury, and lead in diverse cannabis matrices; 2) an ion chromatography–ICP-MS approach for trace Cr(VI) in drinking water; and 3) developments in ICP-MS instrumentation, including collision/reaction cell techniques and single particle analysis for semiconductor applications. A complementary virtual symposium reviewed ICP-MS trends and consumables enhancements.

Methodology and Instrumentation Used

• Cannabis and hemp analysis employs microwave digestion (e.g., CEM MARS 6) followed by Agilent 7850 ICP-MS in helium collision mode with HCl for Hg stabilization and UHMI for matrix tolerance.
• Cr(VI) speciation uses a Metrohm 940 IC with an ASUPP4 column coupled to Agilent 7800 ICP-MS, validated per EPA Method 218.7.
• Semiconductor trace analysis leverages Agilent 8900 ICP-QQQ for challenging elements (Si, P, S, Cl) and spICP-MS on 7800/7850 systems for nanoparticle characterization.
• Consumables include Pt-tipped Ni-plated cones, O-ring-free PFA torches, and pre-cut loops for ISIS 3, enabling robust operation in harsh matrices and simplified maintenance.

Key Results and Discussion

• The AOAC method demonstrated accurate quantification of As, Cd, Hg, and Pb across flower, oils, edibles, and topicals, with IntelliQuant screening confirming Hg and Pb in softgels.
• IC-ICP-MS achieved an MDL of 0.003 µg/L and an MRL of 0.02 µg/L for Cr(VI), meeting California OEHHA goals.
• ICP-QQQ hot plasma and He KED significantly reduced polyatomic interferences, improving detection down to sub-ppt levels.
• spICP-MS revealed membrane–particle interactions affecting ultrafiltration retention and quantified subtle ceria nanoparticle changes during CMP.

Benefits and Practical Applications

• Unified digestion protocols streamline workflows in high-throughput cannabis testing laboratories.
• Species-specific Cr(VI) methods support regulatory compliance in drinking water testing.
• Advanced ICP-MS and consumables provide semiconductor labs with low detection limits, minimal downtime, and reproducible analyses.
• spICP-MS offers insights into nanoparticle behavior in filtration and polishing processes, guiding process optimization.

Future Trends and Opportunities

As regulatory frameworks evolve, demand for multi-element, species-specific, and nanoparticle analyses will grow. Emerging areas include integration of ICP-MS with machine learning for predictive quality control, further miniaturization of sample introduction, and automated consumable management for 24/7 operation. Continuous development of collision gases and reaction cell technology will push detection limits lower and simplify complex matrices.

Conclusion

Recent ICP-MS advances across cannabis safety, water speciation, and semiconductor quality control illustrate the technique’s versatility and sensitivity. Standardized sample preparation, robust instrumentation, and specialized consumables enable analytical laboratories to meet stringent regulatory and industrial requirements while maintaining high throughput and reliability.

References

1. AOAC Official Method for Heavy Metals in Cannabis, First Action, August 2021.
2. Nelson J. et al., Agilent 5994-4080EN, Cannabis Heavy Metals Analysis, 2021.
3. Cheung Y. et al., Agilent 5994-4295EN, IC-ICP-MS Cr(VI) in Drinking Water, 2021.
4. Kubota T., Agilent 5994-1435EN, Rare Earth Interference Correction, 2020.
5. Chan Q. et al., J. Membr. Sci. 599, 117822, 2020; ECS J. Solid State Sci. Technol. 10, 34009, 2021.
6. Agilent Semiconductor Virtual Symposium Recording, September 2021.